(ORDO NEWS) — Over decades of research, scientists have found that large, powerful earthquakes usually occur in groups, rather than randomly. But why, until now, it remained a mystery.
Now a new study, published July 13 in the journal Scientific Reviews, claims that powerful eruptions on the Sun can cause massive earthquakes on Earth.
“Major earthquakes around the world are unevenly distributed … there is a definite connection between them,” says Giuseppe De Natale, scientific director of the National Institute of Geophysics and Volcanology in Rome and co-author of a new study.
“We tested the hypothesis that solar activity can affect the global occurrence of earthquakes.”
Solar Earthquake Origin
To the naked eye, the Sun may seem relatively calm. But our star is constantly bombarding the solar system with a huge amount of energy and particles in the form of the solar wind.
Sometimes, formidable eruptions on the surface of the Sun cause an ejection of coronal mass or powerful energy fluxes of particles – including ions and electrons – that travel through the solar system at breakneck speed.
When they reach the Earth, these charged particles can interfere with the work of satellites and under extreme conditions destroy energy networks.
A new study suggests that particles from powerful eruptions like this – in particular, positively charged ions – may be responsible for triggering a series of strong earthquakes.
Earthquakes usually occur when the rocks are grinding each other, when the tectonic plates of the Earth move and collide. When the strong friction that ties the plates together is overcome, the stones break, releasing a tremendous amount of energy and shaking the earth.
But scientists also noticed a pattern in some large earthquakes around the planet: they usually occur in groups, rather than randomly. This suggests that there may be some kind of global phenomenon that triggers these worldwide series of earthquakes. And although many researchers have already conducted statistical studies, trying to determine the cause, so far no convincing theory has been proven.
Thus, to solve this protracted riddle, the researchers studied 20-year data on both earthquakes and solar activity, looking for any possible matches. In particular, the team used data from the NASA-ESA Solar and Heliospheric Observatory (SOHO) satellite, measurements of protons (positively charged particles) that come from the Sun and wash our planet.
Soho, which is 1.45 million kilometers from Earth, keeps its sight in the sun, which helps scientists keep track of how much solar material falls on our planet.
Comparing the ISC-GEM global earthquake instrumental catalog — the historical record of strong earthquakes — with SOHO data, scientists noticed that more powerful earthquakes occur when the number and velocity of incoming solar protons increase.
In particular, when the proton flux from the Sun reached its peak, over the next 24 hours there was a surge of earthquakes with a magnitude above 5.6.
“This statistical test of the hypothesis is very important,” says De Natal. “The likelihood that this is just a coincidence that we are observing this is very, very small – less than 1 in 100,000.”
Piezoelectric origin of earthquakes
Having noticed a correlation between the flux of solar protons and strong earthquakes, the researchers proposed a possible explanation: a mechanism called the inverse piezoelectric effect.
Previous experiments have clearly shown that the compression of quartz, a rock distributed in the earth’s crust, can generate an electrical impulse using a process known as the piezoelectric effect.
Researchers believe that such small pulses can destabilize faults that are already close to breaking, causing earthquakes. In fact, signatures of electromagnetic events – such as lightning and radio waves earthquakes – have been recorded, occurring along with earthquakes in the past.
Some researchers believe that these events are caused by the earthquakes themselves. But several other studies have discovered strong electromagnetic anomalies before large earthquakes, and not after them, so the exact nature of the relationship between earthquakes and electromagnetic phenomena is still under discussion.
A new explanation, however, turns this electromagnetic causal relationship upside down, suggesting that electromagnetic anomalies are not the result of earthquakes, but rather cause them.
When the positively charged protons of the Sun crash into the Earth’s protective magnetic bubble, they create electromagnetic currents that propagate around the globe. The pulses created by these currents can then deform quartz in the earth’s crust, eventually causing earthquakes.
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